Modified Version of Baby-Led Weaning Does Not Result in Lower Zinc Intake or Status in Infants: A Randomized Controlled Trial

Abstract

Background: Little is known about zinc intakes and status during complementary feeding. This is particularly true for baby-led approaches, which encourage infants to feed themselves from the start of complementary feeding, although self-feeding may restrict the intake of zinc-rich foods.

Objective: To determine the zinc intakes, sources, and biochemical zinc status of infants following Baby-Led Introduction to SolidS (BLISS), a modified version of Baby-Led Weaning (BLW), compared with traditional spoon-feeding.

Design: Secondary analysis of the BLISS randomized controlled trial.

Participants/setting: Between 2012 and 2014, 206 community-based participants from Dunedin, New Zealand were randomized to a Control or BLISS group.

Intervention: BLISS participants received eight study visits (antenatal to 9 months) providing education and support regarding BLISS (ie, infant self-feeding from 6 months with modifications to address concerns about iron, choking, and growth).

Main outcome measures: Dietary zinc intakes at 7 and 12 months (weighed 3-day diet records) and zinc status at 12 months (plasma zinc concentration).

Statistical analyses performed: Regression analyses were used to investigate differences in dietary intakes and zinc status by group, adjusted for maternal education and parity and infant age and sex.

Results: There were no significant differences in zinc intakes between BLISS and Control infants at 7 (median: 3.5 vs 3.5 mg/day; P=0.42) or 12 (4.4 vs 4.4 mg/day; P=0.86) months. Complementary food groups contributing the most zinc at 7 months were "vegetables" for Control infants, and "breads and cereals" for BLISS infants, then "dairy" for both groups at 12 months. There was no significant difference in mean±standard deviation plasma zinc concentration between the Control (62.8±9.8 μg/dL [9.6±1.5 μmol/L]) and BLISS (62.8±10.5 μg/dL [9.6±1.6 μmol/L]) groups (P=0.75).

Conclusions: BLISS infants achieved similar zinc intake and status to Control infants. However, the BLISS intervention was modified to increase iron intake, which may have improved zinc intake, so these results should not be generalized to infants following unmodified BLW.

Keywords: Baby-Led Weaning; Complementary feeding; Infants; Zinc intake; Zinc status.